Glywysing

Glywysing, also known as Gliwissig, was a Welsh petty kingdom which existed from the 5th century AD to 1090, with Cardiff serving as its capital. Glywysing was named for its early monarch Glywys, who was, in turn, named for the city of Glevum (Gloucester). After the death of Glywyg, the kingdom was divided into seven cantrefs for his sons, and it warred with the Kingdom of Gwent and the Kingdom of Dyfed for centuries, losing Cydweli and Gower to Dyfed during the early 8th century before reclaiming the lost lands in 928. In 1055, it became a part of the greater Welsh kingdom under Gruffydd ap Llywelyn, and it was in union with Morgannwg in 1063. In 1090, the last native king of Glywysing, Iestyn ap Gwrgan, was deposed by the Normans during the English conquest of Wales.